Firewall is a network security device that observes and filters incoming and outgoing network traffic, adhering to the security policies defined by an organization. Essentially, it acts as a protective wall between a private internal network and the public Internet.

Fencing your property protects your house and keeps trespassers at bay; similarly, firewalls are used to secure a computer network. Firewalls are network security systems that prevent unauthorized access to a network. It can be a hardware or software unit that filters the incoming and outgoing traffic within a private network, according to a set of rules to spot and prevent cyberattacks.

Firewalls are used in enterprise and personal settings. They are a vital component of network security. Most operating systems have a basic built-in firewall. However, using a third-party firewall application provides better protection.

Now that we have understood what is firewall, moving forward we will see the history of firewalls.

Types of Firewalls:

A firewall can either be software or hardware. Software firewalls are programs installed on each computer, and they regulate network traffic through applications and port numbers. Meanwhile, hardware firewalls are the equipment established between the gateway and your network. Additionally, you call a firewall delivered by a cloud solution as a cloud firewall.

There are multiple types of firewalls based on their traffic filtering methods, structure, and functionality. A few of the types of firewalls are:

Packet Filtering:

A packet filtering firewall controls data flow to and from a network. It allows or blocks the data transfer based on the packet’s source address, the destination address of the packet, the application protocols to transfer the data, and so on.

Proxy Service Firewall:

This type of firewall protects the network by filtering messages at the application layer. For a specific application, a proxy firewall serves as the gateway from one network to another.

Stateful Inspection:

Such a firewall permits or blocks network traffic based on state, port, and protocol. Here, it decides filtering based on administrator-defined rules and context.

Next-Generation Firewall:

According to Gartner, Inc.’s definition, the next-generation firewall is a deep-packet inspection firewall that adds application-level inspection, intrusion prevention, and information from outside the firewall to go beyond port/protocol inspection and blocking.

Unified Threat Management (UTM) Firewall:

A UTM device generally integrates the capabilities of a stateful inspection firewall, intrusion prevention, and antivirus in a loosely linked manner. It may include additional services and, in many cases, cloud management. UTMs are designed to be simple and easy to use.

Threat-Focused NGFW:

These firewalls provide advanced threat detection and mitigation. With network and endpoint event correlation, they may detect evasive or suspicious behavior.

How Does a Firewall Work?

As mentioned previously, firewalls filter the network traffic within a private network. It analyses which traffic should be allowed or restricted based on a set of rules. Think of the firewall like a gatekeeper at your computer’s entry point which only allows trusted sources, or IP addresses, to enter your network.

A firewall welcomes only those incoming traffic that has been configured to accept. It distinguishes between good and malicious traffic and either allows or blocks specific data packets on pre-established security rules.

These rules are based on several aspects indicated by the packet data, like their source, destination, content, and so on. They block traffic coming from suspicious sources to prevent cyberattacks.

For example, the image depicted below shows how a firewall allows good traffic to pass to the user’s private network.

Why Are Firewalls Important?

Firewalls are designed with modern security techniques that are used in a wide range of applications. In the early days of the internet, networks needed to be built with new security techniques, especially in the client-server model, a central architecture of modern computing. That’s where firewalls have started to build the security for networks with varying complexities. Firewalls are known to inspect traffic and mitigate threats to the devices.

Uses of Firewalls:

Firewalls can be used in corporate as well as consumer settings.

Firewalls can incorporate a security information and event management strategy (SIEM) into cybersecurity devices concerning modern organizations and are installed at the network perimeter of organizations to guard against external threats as well as insider threats.

Firewalls can perform logging and audit functions by identifying patterns and improving rules by updating them to defend the immediate threats.

Firewalls can be used for a home network, Digital Subscriber Line (DSL), or cable modem having static IP addresses. Firewalls can easily filter traffic and can signal the user about intrusions.

They are also used for antivirus applications.

When vendors discover new threats or patches, the firewalls update the rule sets to resolve the vendor issues.

In-home devices, we can set the restrictions using Hardware/firmware firewalls.

Advantages of Using Firewalls:

Now that you have understood the types of firewalls, let us look at the advantages of using firewalls.

Firewalls play an important role in the companies for security management. Below are some of the important advantages of using firewalls.

It provides enhanced security and privacy from vulnerable services. It prevents unauthorized users from accessing a private network that is connected to the internet.

Firewalls provide faster response time and can handle more traffic loads.

A firewall allows you to easily handle and update the security protocols from a single authorized device.

It safeguards your network from phishing attacks.

Conclusion:

In this tutorial on what is a firewall, you have understood what a firewall is and how it works. You also learned the different types of firewalls and how to use a firewall. Cybersecurity is a booming field in today’s times. If you are looking to learn ethical hacking to protect devices and networks from cybercriminals. In that case, Simplilearn’s Cyber bootcamp, CEH v11 – Certified Ethical Hacking Course will help you master advanced network packet analysis and penetration testing techniques to build your network security skill-set.

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